1. Field of the Invention
This invention relates to a surface treating method for treating an internal wall and internal elements of a vacuum apparatus in which processing and treatment are performed under vacuum atmosphere, particularly, a vacuum treatment apparatus in which a thin film of a dielectric, a semiconductor, or the like is applied to the surface of a substrate by a vapor deposition method in a vacuum processing apparatus in which etching or the like is performed. Further, it relates to the construction material for the vacuum apparatus the surface of which is treated by said surface treating method and to the vacuum treatment apparatus made from the treated material. As used herein, the term `construction material` refers to an element of a vacuum apparatus.
2. Description of the Prior Art
As a construction material for a vacuum apparatus, a material having a surface which is chemically and thermally stable and which releases gas as little as possible under vacuum is desired. Also, a material constituting a vacuum chamber is required to have sufficient mechanical strength to withstand high pressure.
Therefore, the construction materials employed in the conventional apparatuses have been generally stainless steel or steel electroplated with nickel. However, they have had a defect that a large quantity of the gas is released under vacuum. Further, vacuum processing apparatuses using an etching gas such as CF.sub.4 and the like have had a problem in the corrosion resistance of the materials.
For this reason, for example, an aluminum material which releases little gas as compared with the above metal materials, and further, which is excellent in corrosion resistance to the above etching gas has been used as a construction material or coating material in recent years.
In the case of using an aluminum material as a construction material for a vacuum apparatus, the construction material is cut from a block material of aluminum, and in the case of using an aluminum material as a coating material, the aluminum film is coated by a vapor deposition method on the surface of the construction material such as stainless steel and the like.
However, the former has the disadvantage, for example, that it is necessary to make the chamber wall thicker from a standpoint of mechanical strength in the case of a large-sized vacuum chamber. The latter is limited in the size and shape of a construction material that can be coated by the vapor deposition, and in thickness of aluminum film that can be vapor-deposited.
Further, the latter method has the following problems.
(1) The productivity is poor since the vacuum apparatus must be used in the method and it takes a long time to exhaust the gas in the apparatus. PA1 (2) In the case where the construction material for the vacuum apparatus to be treated by the vapor deposition is large, the productivity becomes even poorer since a large-sized vacuum apparatus is necessarily required. PA1 (3) In the case where the above construction material for the vacuum apparatus has a complex shape, a complicated operation is required to form a vapor deposition film having a uniform film thickness over each part.